JPS5937351Y2 - Perfect circle holder for pipes - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a round holder for pipes used when connecting large-diameter thin-walled steel pipes with welded joints.

Conventionally, buried steel pipes for water conveyance are constructed so that as the pipe diameter 2 of the steel pipe 1 increases, the pipe thickness 3 becomes thicker, and the pipe diameter/thickness ratio is 100 to 150). Even after relatively rough repair work, there was no noticeable deformation of the pipe body, and it did not interfere with on-site work such as welding.However, as the pipe diameter increases, the pipe thickness can be increased without limit. Since this is difficult in practice, as the diameter increases, a supplementary steel pipe 5 is used, which has ribs 4 attached to the outer periphery of the pipe to increase its rigidity, as shown in Fig. 2, but this steel pipe is expensive. is high and undesirable.

In recent years, it has been theoretically discovered that if civil engineering work such as backfilling is carried out with careful consideration, it is possible to reduce the thickness of the pipe to a certain extent by considering the earth and sand around the buried pipe as a single structure. , We are beginning to see examples of construction based on this theory.

However, thin-walled large-diameter steel pipes bend significantly due to their own weight, so during on-site welding work, they are held straight and perfectly round from inside the pipe using rod jacks; There are drawbacks such as the contact part of the jack protruding in an abnormally convex shape and the need to prevent the jack from tipping over.

In order to solve this drawback, the following method was attempted.

That is, in FIGS. 8a and 8b, a quarter-shaped outer circumference straightening ring 8 made by bending H-beam steel according to the outer diameter of the tube body 1 is placed on the tube body, and the tube body 7 is placed on the upper surface thereof. Engaging the top surface 11 of the double-shaped horse 10 to which the foot portion 9 is welded,
By driving a wedge-shaped arrow 12 between the two retaining surfaces, the deflection of the tubular body is forcibly corrected.

The correction ring is 100 to 300rr from the pipe port 13.
It is installed at rIn.

In this method, it is necessary to temporarily weld the horse 10 to the tube body 7, and the welding and subsequent removal work is complicated, and the driving work requires a large number of man-hours because it requires a large number of rotations and arrows. In addition, after straightening the pipe body to a perfect circle, it is hoisted up by a crane for welding or piping installation, and while being twisted or shaken laterally, the horse There have been problems such as the arrows 12 breaking, the arrows falling off and the straightening ring moving, causing deflection, or the arrows 12 falling off scattering and causing harm to nearby workers.

In addition, in order to arrange the backing metal 15 in the groove portion 14 of both the pipe bodies 7 to be connected, as shown in FIGS. After temporarily welding the leg part 9 of the two-shaped horse 10 to the circumferential side, while driving the arrow 12 between the backing metal and the tube body, temporary welding is performed while eliminating the gap between the backing metal and the tube body. This is done by removing the horse from the pipe body after applying the attachment, but the marks of this removal remain as scratches, so it is necessary to add touch-up work.
This is the cause of rising costs.

This invention was made in view of the current situation, and the embodiments thereof will now be explained with reference to the drawings.
The outer circumferential correction ring 11 is formed by a three-part ring made of H-beam steel that has been subjected to circular arc bending in the in-plane direction of its web in alignment with the above, and connecting fittings 18 are used to fasten each of the correction rings. The three dividing points of the correction ring may be equally divided into 0 degrees, 120 degrees, and 240 degrees, or other dividing points may be selected depending on the pipe diameter and the local situation of the work place.

The web portion 19 of each split ring has connecting bolt holes 20, 20', 30, 30', 40, 40, respectively at both ends.
For convenience of explanation, the large number is 20' for the hole 20 at the adjacent end of the adjacent ring.
They are numbered so that 30 corresponds to 30' and 40 corresponds to 40'.

A large number of intermediate holes 21 are bored in the middle of the web portion of each ring.

The connecting fitting 18 has a plate shape having a width approximately equal to the height of the side wall, and has holes at both ends thereof having the same diameter as the straightening ring connecting bolt hole.
In addition, connection holes 22 and 22' are formed in alignment with the holes 20 and 20', etc., and can be freely fastened with bolts or the like.

1. The use of the perfect circle holder consisting of the outer periphery correction ring 17 and the connecting fitting 18 according to this invention will be described in detail.
Without unscrewing, the two dividing points of the correction ring are connected in advance in the connection hole by the connecting fitting 18 and bolts manually by an operator, and a straight shackle or the like is inserted into the intermediate hole between the two correction rings at the remaining dividing point. A known tightening machine (not shown) connected to the straightening ring is provided, and the tightening machine is operated to attract the straightening ring, and then the straightening ring is tightened with a metal fitting in the connecting hole, so that the straightening ring is in a deflected state. The tube mouth is made perfectly circular according to the inner diameter of the entire straightening ring.

Also, regarding the installation of the backing metal of the pipe groove part using the perfect circle holder according to this invention, Nos. 10a and 1
0b, the straightening ring 17 is placed between the back side of the groove part 14, and the support rod 23 is inserted through the intermediate hole 21 in the side wall of the straightening ring 17, and then the backing metal 15 is placed on the back side of the groove part. Wedge-shaped arrows 12 are driven between the support rod and the backing metal by rolling it up, and many of the arrows are driven into the gap between the tube body and the backing metal to make them come into contact with each other. After eliminating gaps around the entire circumference, the backing metal is tack welded.

Therefore, unlike the conventional method, there is no need to temporarily attach a large number of horses, which is extremely efficient, and also greatly contributes to cost reduction.

As mentioned above, this invention eliminates the need for temporarily welding and removing a large number of double-shaped horses to maintain a perfect circle, and also eliminates the manual work of driving wedge-shaped arrows to apply correction force. In addition to eliminating the need for arrows, it is possible to improve the dangerous work environment where the arrows can scatter and cause harm, and correction work can be carried out extremely quickly and safely. For example, as mentioned above, this invention has great industrial utility value, such as being efficient without requiring a Z-shaped horse.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a buried steel pipe, Fig. 2 is a perspective view showing an example of a stiffening steel pipe with ribs, Fig. 3 is a plan view of an outer periphery straightening ring according to an embodiment of this invention, and Fig. 4 5 is a partially enlarged plan view of the previous figure, FIG. 5 is a cross-sectional view taken along line A-A of the previous figure, FIG. 6 is a plan view of the connecting fitting, and FIG. The figure is a partially enlarged perspective plan view showing the attachment of a conventional outer periphery correction ring, FIG. 8b is a front view, FIG. 9a is a partially enlarged perspective view showing the attachment of a conventional backing metal, and FIG. 10a is a perspective view showing a state in which the correction ring according to the invention is applied to the mounting of a backing metal;
FIG. 10b is a previous sectional view taken along line DD. 7... Tube body, 10... Two-figure horse, 12... Wedge-shaped arrow, 17... Outer circumference correction ring, 18... Connection fitting.

Claims (1)

[Scope of utility model registration request] When connecting large-diameter, thin-walled steel pipes with welded joints, the roundness holder is fitted onto the outer periphery of the ends of the connecting pipes and tightened to maintain the roundness of the ends of the connecting pipes. The straightening ring consists of a three-part ring made by bending an H-shaped steel in an arc in its web plane, and each split ring has bolt holes for connecting and tightening the ends of each other by a tightening machine using a connecting fitting. on the web portions at both ends, and when a pair of straightening rings face each other with the welded joint in between, a support rod can be passed between both rings to hold down the welding backing metal that is in close contact with the welded joint. H of each split ring
A perfect circle holder for a tube, characterized in that the shaped steel web portion has a plurality of intermediate holes in addition to the bolt holes at both ends.